Semiconductor device, mounting substrate and method of manufacturing mounting substrate, circuit board, and electronic instrument

ABSTRACT

There is provided a semiconductor device comprising: a first plating layer formed on one surface of an interconnect pattern; a second plating layer formed within through holes in the interconnect pattern; a semiconductor chip electrically connected to the first plating layer; an anisotropic conductive material provided on the first plating layer; and a conductive material provided on the second plating layer, wherein the first plating layer has appropriate adhesion properties with the anisotropic conductive material, and the second plating layer has appropriate adhesion properties with the conductive material.

TECHNICAL FIELD

The present invention relates to a semiconductor device, a mountingsubstrate and method of manufacturing the mounting substrate, a circuitboard, and an electronic instrument.

BACKGROUND ART

Semiconductor devices such as T-CSP (Tape-Chip Scale/Size Package) areknown, which use a substrate on which an interconnect pattern is formed.Commonly, a semiconductor chip is mounted on the substrate, and with theelectrodes of the semiconductor chip electrically connected to theinterconnect pattern, solder balls are provided. The characteristicsrequired of the surface of the interconnect pattern for connecting theelectrodes of the semiconductor chip and the characteristics requiredfor providing the solder balls are different. Although the surface ofthe interconnect pattern requires locally varying characteristics,conventionally the whole of the surface of the interconnect pattern hasbeen subjected to a single plating operation.

DISCLOSURE OF THE INVENTION

The present invention solves the above described problem, and has as itsobjective the provision of a semiconductor device including aninterconnect pattern having portions of its surface with differentproperties, and similarly a mounting substrate and method of manufacturethereof, a circuit board, and an electronic instrument.

(1) A semiconductor device of the present invention comprises:

-   -   a substrate in which a plurality of through holes are formed;    -   an interconnect pattern formed on the substrate and passing over        the through holes;    -   a first plating layer formed on the interconnect pattern surface        opposite to the substrate;    -   a second plating layer formed on the interconnect pattern        surface looking toward the substrate in the through holes;    -   a semiconductor chip mounted on the substrate and electrically        connected to the first plating layer;    -   a resin provided on the first plating layer; and    -   a conductive material provided on the second plating layer,    -   wherein the first and second plating layers have different        properties.

According to the present invention, since the first and second platinglayers are formed on the interconnect pattern, oxidation of the surfaceof the interconnect pattern can be prevented, and also the electricalcontact resistance can be lowered.

The first and second plating layers have different characteristics. Aplating layer having appropriate adhesion properties with a resin and aplating layer having appropriate adhesion with a conductive materialcommonly require different properties. The present invention providesfor this by means of the first and second plating layers of differentproperties.

(2) A semiconductor device of the present invention comprises:

-   -   a substrate;    -   a first interconnect pattern formed on one surface of the        substrate;    -   a second interconnect pattern formed on the other surface of the        substrate and electrically connected to the first interconnect        pattern;    -   a first plating layer formed on the first interconnect pattern        surface opposite to the substrate;    -   a second plating layer formed on the second interconnect pattern        surface opposite to the substrate;    -   a semiconductor chip mounted on the substrate and electrically        connected to the first plating layer;    -   a resin provided on the first plating layer; and    -   a conductive material provided on the second plating layer,    -   wherein the first and second plating layers have different        properties.

According to the present invention, since the first and second platinglayers are formed on the first and second interconnect patterns,oxidation of the surface of the first and second interconnect patternscan be prevented, and also electrical contact resistance can be lowered.The first and second plating layers have different characteristics. Aplating layer having appropriate adhesion properties with a resin and aplating layer having appropriate adhesion with a conductive materialcommonly require different properties. The present invention providesfor this by means of the first and second plating layers of differentproperties.

(3) A semiconductor device of the present invention comprises:

-   -   a substrate;    -   an interconnect pattern formed on the substrate;    -   a first plating layer formed on a first portion of the        interconnect pattern surface opposite to the substrate;    -   a second plating layer formed on a second portion of the        interconnect pattern surface opposite to the substrate;    -   a resin provided on the first plating layer;    -   a conductive material provided on the second plating layer; and    -   a semiconductor chip mounted on the substrate and electrically        connected to the conductive material,    -   wherein the first and second plating layers have different        properties.

According to the present invention, since the first and second platinglayers are formed on the interconnect pattern, oxidation of the surfaceof the interconnect pattern can be prevented, and the electrical contactresistance can be lowered. The first and second plating layers havedifferent characteristics. A plating layer having appropriate adhesionproperties with a resin, and a plating layer having appropriate adhesionwith a conductive material commonly require different properties. Thepresent invention provides for this by means of the first and secondplating layers of different properties.

(4) In this semiconductor device, the first plating layer may be formedto be thinner than the second plating layer.

By making the plating layer thinner, the adhesion properties with theresin are improved, and if the plating layer is made thicker, excellentbonding with the conductive material is obtained.

(5) In this semiconductor device, the first and second plating layersmay be formed of different materials.

The first plating layer can be formed of a material improving theadhesion properties with a resin, and the second plating layer can beformed of a material having excellent bonding with the conductivematerial.

(6) In this semiconductor device, the resin may be an adhesive, andinclude conductive particles to constitute an anisotropic conductivematerial; and the semiconductor chip may be mounted by face-down bondingwith the anisotropic conductive material interposed.

According to this, an anisotropic conductive material is provided on thefirst plating layer, and the first plating layer has appropriateadhesion properties with the adhesive of the anisotropic conductivematerial. By the formation of the first plating layer, in the face-downbonding of the semiconductor chip, the electrical contact resistance islowered.

(7) A mounting substrate of the present invention comprises:

-   -   a substrate in which a plurality of through holes are formed;    -   an interconnect pattern formed on the substrate and passing over        the through holes;    -   a first plating layer formed on the interconnect pattern surface        opposite to the substrate; and    -   a second plating layer formed on the interconnect pattern        surface looking toward the substrate in the through holes,    -   wherein the first and second plating layers have different        properties.

According to the present invention, since the first and second platinglayers are formed on the interconnect pattern, oxidation of the surfaceof the interconnect pattern can be prevented, and also the electricalcontact resistance can be lowered. The first and second plating layershave different characteristics. A plating layer having appropriateadhesion properties with a resin, and a plating layer having appropriateadhesion with a conductive material commonly require differentproperties. The present invention provides for this by means of thefirst and second plating layers of different properties.

(8) A mounting substrate of the present invention comprises:

-   -   a substrate;    -   a first interconnect pattern formed on one surface of the        substrate;    -   a second interconnect pattern formed on the other surface of the        substrate and electrically connected to the first interconnect        pattern;    -   a first plating layer formed on the first interconnect pattern        surface opposite to the substrate; and    -   a second plating layer formed on the second interconnect pattern        surface opposite to the substrate,    -   wherein the first and second plating layers have different        properties.

According to the present invention, since the first and second platinglayers are formed on the first and second interconnect patterns,oxidation of the surface of the first and second interconnect patternscan be prevented, and also the electrical contact resistance can belowered. The first and second plating layers have differentcharacteristics. A plating layer having appropriate adhesion propertieswith a resin, and a plating layer having appropriate adhesion with aconductive material commonly require different properties. The presentinvention provides for this by means of the first and second platinglayers of different properties.

(9) A mounting substrate of the present invention comprises:

-   -   a substrate;    -   an interconnect pattern formed on the substrate;    -   a first plating layer formed on a first portion of the        interconnect pattern surface opposite to the substrate; and    -   a second plating layer formed on a second portion of the        interconnect pattern surface opposite to the substrate,    -   wherein the first and second plating layers have different        properties.

According to the present invention, since the first and second platinglayers are formed on the interconnect pattern, oxidation of the surfaceof the interconnect pattern can be prevented, and also the electricalcontact resistance can be lowered. The first and second plating layershave different characteristics. A plating layer having appropriateadhesion properties with a resin, and a plating layer having appropriateadhesion with a conductive material commonly require differentproperties. The present invention provides for this by means of thefirst and second plating layers of different properties.

(10) In this mounting substrate, the first plating layer may be formedto be thinner than the second plating layer.

By making the plating layer thinner, the adhesion properties with theresin are improved, and if the plating layer is made thicker, excellentbonding with the conductive material is obtained.

(11) In this mounting substrate, the first and second plating layers maybe formed of different materials.

The first plating layer can be formed of a material improving theadhesion properties with a resin, and the second plating layer can beformed of a material having excellent bonding with the conductivematerial.

(12) On a circuit board of the present invention, the above-describedsemiconductor device is mounted.

(13) An electronic instrument of the present invention is equipped withthe above-described semiconductor device.

(14) A method of manufacturing a mounting substrate of the presentinvention comprises the steps of:

-   -   immersing a substrate in a plating bath, the substrate having a        plurality of through holes and an interconnect pattern formed        thereon and passsing over the through holes;    -   electrically connecting the interconnect pattern to a cathode;    -   disposing a first anode to face the surface of the substrate on        which the interconnect pattern is formed;    -   disposing a second anode to face the surface of the substrate        opposite to the interconnect pattern, and    -   passing currents of different current densities between the        first and second anodes and the cathode,    -   wherein a first plating layer is formed on the interconnect        pattern by the current from the first anode; and    -   wherein a second plating layer is formed on the interconnect        pattern on the side of the substrate and within the through        holes by the current from the second anode.

According to the present invention, a first plating layer can be formedon one surface of the interconnect pattern by the current from the firstanode, and a second plating layer can be formed on the other surface ofthe interconnect pattern by the current from the second anode. It shouldbe noted that the second plating layer is formed on the portion of theinterconnect pattern exposed from the through holes.

(15) A method of manufacturing a mounting substrate of the presentinvention comprises the steps of:

-   -   immersing a substrate in a first plating bath, the substrate        having a plurality of through holes and an interconnect pattern        formed thereon and passsing over the through holes;    -   electrically connecting the interconnect pattern to a cathode;    -   forming a first plating layer on the interconnect pattern by        disposing a first anode to face the surface of the substrate on        which the interconnect pattern is formed and carrying out        electroplating;    -   immersing the substrate in a second plating bath;    -   electrically connecting the interconnect pattern to a cathode;        and    -   forming a second plating layer on the interconnect pattern        surface looking toward the substrate in the through holes by        disposing a second anode to face the surface of the substrate        opposite to the interconnect pattern and carrying out        electroplating.

According to the present invention, the substrate is immersed in firstand second plating baths, and a first plating layer is formed on onesurface of the interconnect pattern, and a second plating layer isformed on the other surface of the interconnect pattern.

(16) A method of manufacturing a mounting substrate of the presentinvention comprises the steps of:

-   -   forming a plurality of through holes and an interconnect pattern        passing over the through holes on a substrate;    -   forming a first plating layer by covering the through holes with        a first resist and applying electroless plating to the        interconnect pattern; and    -   forming a second plating layer by exposing a portion of the        interconnect pattern in the through holes, covering the surface        of the interconnect pattern opposite to the substrate with a        second resist, and applying electroless plating to the        interconnect pattern in the through holes.

According to the present invention, the first and second plating layersare formed by the two operations of electroless plating.

(17) A method of manufacturing a mounting substrate of the presentinvention comprises the steps of:

-   -   immersing a substrate in a plating bath, wherein the substrate        has a first interconnect pattern formed on one surface and a        second interconnect pattern electrically connected to the first        interconnect pattern and formed on the other surface;    -   electrically connecting the first and second interconnect        patterns to a cathode;    -   disposing a first anode to face the first interconnect pattern;    -   disposing a second anode to face the second interconnect        pattern; and    -   passing currents of different current densities between the        first and second anodes and the cathode,    -   wherein a first plating layer is formed on the first        interconnect pattern by the current from the first anode; and    -   wherein a second plating layer is formed on the second        interconnect pattern by the current from the second anode.

According to the present invention, a first plating layer can be formedon the first interconnect pattern by the current from the first anode,and a second plating layer can be formed on the second interconnectpattern by the current from the second anode.

(18) A method of manufacturing a mounting substrate of the presentinvention comprises the steps of:

-   -   immersing a substrate in a first plating bath, wherein the        substrate has a first interconnect pattern formed on one surface        and a second interconnect pattern electrically connected to the        first interconnect pattern and formed on the other surface;    -   electrically connecting the first interconnect pattern to a        cathode;    -   forming a first plating layer on the first interconnect pattern,        by disposing a first anode to face the first interconnect        pattern and carrying out electroplating;    -   immersing the substrate in a second plating bath;    -   electrically connecting the second interconnect pattern to a        cathode; and    -   forming a second plating layer on the second interconnect        pattern, by disposing a second anode to face the second        interconnect pattern and carrying out electroplating.

According to the present invention, the substrate is immersed in firstand second plating baths, a first plating layer is formed on the firstinterconnect pattern, and a second plating layer is formed on the secondinterconnect pattern.

(19). A method of manufacturing a mounting substrate of the presentinvention comprises the steps of:

-   -   forming a first interconnect pattern on one surface of a        substrate;    -   forming a second interconnect pattern electrically connected to        the first interconnect pattern on the other surface of the        substrate;    -   forming a first plating layer by covering the second        interconnect pattern with a first resist and applying        electroless plating to the first interconnect pattern; and    -   forming a second plating layer by covering the first        interconnect pattern with a second resist and applying        electroless plating to the second interconnect pattern.

According to the present invention, the first and second plating layersare formed by the two operations of electroless plating.

(20) A method of manufacturing a mounting substrate of the presentinvention comprises the steps of:

-   -   forming an interconnect pattern on a substrate;    -   forming a first plating layer on a first portion of the        interconnect pattern by covering a second portion of the        interconnect pattern with a resist and exposing the first        portion, and applying electroless plating to the interconnect        pattern; and    -   forming a second plating layer in the second portion by covering        the first portion with a resist and exposing the second portion,        and applying electroless plating to the interconnect pattern.

According to the present invention, the first and second plating layersare formed by the two operations of electroless plating.

(21) In this method of manufacturing a mounting substrate, the first andsecond plating layers may have different properties.

A plating layer having appropriate adhesion properties with a resin, anda plating layer having appropriate adhesion with a conductive materialcommonly require different properties. In this case, by making thecurrent densities between the first and second anodes and the cathodedifferent, first and second plating layers of different thicknesses maybe formed. Alternatively, by making the plating fluids in the first andsecond plating baths different, or making the current densities betweenthe first and second anodes and the cathode different, first and secondplating layers of different thicknesses may be formed.

(22) In this method of manufacturing a mounting substrate, the firstplating layer may be formed to be thinner than the second plating layer.

By making the plating layer thinner, the adhesion properties with theresin are improved, and if the plating layer is made thicker, excellentbonding with the conductive material is obtained.

(23) In this method of manufacturing a mounting substrate, the first andsecond plating layers may be formed of different materials.

The first plating layer can be formed of a material improving theadhesion properties with a resin, and the second plating layer can beformed of a material having excellent bonding with the conductivematerial.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a semiconductor device according to a first embodiment ofthe present invention.

FIG. 2 shows a substrate of a semiconductor device according to thefirst embodiment of the present invention.

FIG. 3 shows a mounting substrate used in the first embodiment of thepresent invention.

FIG. 4 shows a method of manufacturing a mounting substrate according tothe first embodiment of the present invention.

FIG. 5 shows a method of manufacturing a semiconductor device accordingto the first embodiment of the present invention.

FIG. 6 shows a method of manufacturing a mounting substrate according toa second embodiment of the present invention.

FIGS. 7A and 7B show a method of manufacturing a mounting substrateaccording to a third embodiment of the present invention.

FIG. 8 shows a semiconductor device according to a fourth embodiment ofthe present invention.

FIGS. 9A and 9B show a substrate of a semiconductor device according tothe fourth embodiment of the present invention.

FIG. 10 shows a semiconductor device according to a fifth embodiment ofthe present invention.

FIGS. 11A and 11B show a method of manufacturing a mounting substrateaccording to the fifth embodiment of the present invention.

FIG. 12 shows a circuit board to which the present invention is applied.

FIG. 13 shows an electronic instrument equipped with a semiconductordevice fabricated with application of the method of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is now described in terms of a number of preferredembodiments, with reference to the drawings.

First Embodiment

FIG. 1 shows a first embodiment of the semiconductor device of thepresent invention. A semiconductor device 1 comprises a semiconductorchip 10 and a substrate 20. When the plan view form of the semiconductorchip 10 is a rectangle (a square or an oblong), along at least one side(which case includes a pair of opposing sides or all four sides), on onesurface of the semiconductor chip 10 (the active surface) a plurality ofelectrodes 12 may be formed. Alternatively, the plurality of electrodes12 may be arranged in the center of the semiconductor chip 10 or thevicinity thereof. On the electrodes 12 are provided bumps 14 in the formof solder balls, gold wire balls, gold plating, or the like. Theelectrodes 12 themselves may be in the form of bumps. Between theelectrodes 12 and the bumps 14, a layer to prevent the diffusion of thebump metal, of nickel, chromium, titanium, or the like, may be applied.

There is no particular restriction on the overall form of the substrate20, which may be a rectangle, polygon, or a combination of a pluralityof rectangles, and can be a similar figure of the plan view form of thesemiconductor chip 10. The thickness of the substrate 20 is commonlydetermined by the material used, and is not subject to particularrestriction. The substrate 20 may be formed of an organic or inorganicmaterial, or may be constituted of a combination thereof. The substrate20 may be a flexible substrate, or may equally be a rigid substrate. Thesubstrate 20 can be formed by punching out from a flexible substrate inthe form of a tape formed of an organic resin.

FIG. 2 is a plan view of the substrate of the semiconductor device shownin FIG. 1. As shown in FIGS. 1 and 2, on one surface of the substrate 20is formed a plurality of interconnects (leads) 22, which constitute aninterconnect pattern 21. Each of the interconnects 22 has formed lands24 and 26. The lands 24 and 26 are commonly formed to be wider than theinterconnect 22. The one land 26 may be formed in a position close tothe center of the substrate 20, and the other land 24 formed at anintermediate point of the interconnect 22. Of the plurality ofinterconnects 22, at least one or all is or are not electricallyconductive to the other interconnects 22, and is or are electricallyisolated. Of the plurality of interconnects 22, interconnects such asthose connected in common to the power supply or ground of thesemiconductor chip 10 may have the lands 24 and 26 connected together.

In the substrate 20 is formed a plurality of through holes 28. Over eachof the through holes 28 passes one of the interconnects 22. The ends ofthe interconnects 22 may equally be positioned over the through holes28. When a land 26 is formed at the end of an interconnect 22, the land26 is positioned over a through hole 28.

As shown in the enlargement in FIG. 1, the interconnects 22 have formedthereon first and second plating layers 30 and 32. The interconnects 22are formed of copper, or a two-layer construction of platinum andnickel, and the material of the plating layers 30 and 32 can be selectedfrom nickel, palladium, nickel-gold, nickel-palladium-gold, gold,solder, and tin. The first plating layer 30 is formed on the surface ofthe interconnect 22 opposite to that of the substrate 20. The secondplating layer 32 is formed on the surface of the interconnect 22 facingthe substrate 20 within the through hole 28. When a land 26 ispositioned over the through hole 28, the second plating layer 32 isformed on the land 26. The first and second plating layers 30 and 32have different properties as a result of differing in at least either ofthickness or material.

The first plating layer 30 prevents oxidation at least over the land 24,and ensures conduction, and lowers the electrical contact resistance.Even though the first plating layer 30 is formed, intimate contact withthe resin on the interconnects 22 can be obtained. For example, takingas an example of the resin an adhesive of an anisotropic conductivematerial, when nickel is formed as an underlayer for the plating layer30, in order that for example a silane coupling material included in theadhesive forms a chemical compound with the nickel or with its oxide orhydroxide, the plating layer 30 is preferably formed to be thin. Forexample, gold plating of thickness on the order of 0.05 μm can be usedfor the first plating layer 30. This enables a strong bond to beobtained.

On the other hand, the second plating layer 32 is appropriate forbonding to a conductive material, such as for example externalterminals. For example, gold plating of thickness on the order of 0.3 μmas the second plating layer 32 ensures good bonding with the conductivematerial. If the conductive material is solder, solder plating may beused for the second plating layer 32 to ensure good solderingcharacteristics.

The semiconductor chip 10 is mounted on the substrate 20 by face-downbonding. The bumps 14 of the semiconductor chip 10, and theinterconnects 22 formed on the substrate 20 are electrically connected.Since the plating layer 30 is formed on the interconnects 22 asatisfactory electrical connection is obtained. When the lands 24 and 26are formed on the interconnects 22, the lands 24 and bumps 14 areelectrically connected. As a means of the electrical connection may beused an anisotropic conductive material 34 including conductiveparticles in an adhesive formed of a resin. In this case, the conductiveparticles are interposed between the interconnects 22 and the bumps 14to provide electrical conduction. The anisotropic conductive material 34may be an anisotropic conductive film or anisotropic conductiveadhesive.

When the anisotropic conductive material 34 is used, it covers thesurface of the interconnects 22 opposite to the surface of contact withthe substrate 20, the side surfaces and the end surfaces, or in otherwords the surfaces not in contact with the substrate 20. When theanisotropic conductive material 34 is not used, a resin of an underfillmaterial or the like is employed to cover the surfaces of theinterconnects 22 not in contact with the substrate 20. The materialcovering the interconnects 22 may also cover the whole of one surface ofthe substrate 20. Since the first plating layer 30 formed on theinterconnects 22 has appropriate adhesion properties with the resin, theresin provided on the interconnects 22 is less liable to peel off. Thatis to say, the anisotropic conductive material 34 is made less liable topeel off.

On the surface of the interconnects 22 facing the substrate 20, withinthe through holes 28 a conductive material 36 is provided. In moredetail, the conductive material 36 is formed on the second plating layer32, and projects from the through holes 28. The conductive material 36forms external terminals. Since the second plating layer 32 hasappropriate adhesion properties with the conductive material, asatisfactory electrical connection can be obtained between theconductive material 36 and the second plating layer 32. The conductivematerial 36 commonly consists of solder balls, but may equally beplating, or conductive projections of for example conductive resin.

Instead of the external terminals being formed by the conductivematerial 36, the through holes 28 may be filled with the conductivematerial 36, the second interconnects electrically connected to theconductive material 36 may be formed on the other surface of thesubstrate 20, and these second interconnects may be provided withexternal terminals. In this case, since the substrate 20 hasinterconnects formed on both surfaces it is a double-sided substrate.Furthermore, as the substrate 20 may equally be used a multi-layersubstrate or a built-up substrate. When a built-up substrate ormulti-layer substrate is used, if an interconnect pattern is formed on asolid ground layer which extends in plan view, then since a micro-stripconstruction with no surplus interconnect pattern is obtained, thesignal transmission characteristics can be improved.

The above description applies to face-down bonding using the anisotropicconductive material 34, but there is no restriction to this method offace-down bonding, and the present invention can be applied to themethod of applying heat (and if necessary, pressure) to a semiconductorchip with solder bumps, the method of applying heat and pressure (and ifnecessary ultrasound bonding) to a semiconductor chip with gold bumps,or the face-down bonding method using the setting shrinking force of aresin. This applies also to the following embodiments.

In FIG. 1 is shown a fan-in type of semiconductor device in which theconductive material 36 forming the external terminals is provided onlywithin the mounting region of the semiconductor chip 10, but this is notlimitative of the invention. For example, the present invention can beapplied to a fan-out type of semiconductor device in which externalterminals are provided only outside the mounting region of thesemiconductor chip 10, or a fan-in/fan-out type of semiconductor devicein which this is combined with a fan-in type. In a fan-out type orfan-in/fan-out type of semiconductor device, by means of the resinprovided on the interconnects 22, a stiffener may be adhered to theoutside of the semiconductor chip. This applies also to the followingembodiments.

FIG. 3 shows a mounting substrate of the first embodiment of the presentinvention. A mounting substrate 40 shown in FIG. 3 is a tape carrier,and has formed a plurality of interconnect patterns 21 (see FIG. 1) fora plurality of semiconductor devices. Each of the interconnect patterns21 has formed first and second plating layers 30 and 32 (see FIG. 1).The tape carrier formed by the mounting substrate 40 is punched out toobtain mounting substrates corresponding to individual semiconductordevices. A substrate having at least one interconnect pattern 21 formedis a mounting substrate, and the substrate 20 with the interconnectpattern 21 shown in FIG. 1 formed is also a mounting substrate.Alternatively, as a finished product a mounting substrate larger thanthe outline of the semiconductor device may be provided. In this case,before the semiconductor chip is mounted, on a part and preferably atleast half of the outline position of the semiconductor device, one orpreferably a plurality of holes (for example slots) can be formed, andthe remainder of the outline position (for example the portions betweenthe plurality of holes) may be punched out after mounting thesemiconductor chip.

The mounting substrate 40 shown in FIG. 3 includes a substrate 42 inwhich is formed a plurality of through holes 28 (see FIG. 1)., aplurality of interconnect patterns 21 formed on the substrate 42, firstand second plating layers 30 and 32 formed on the interconnects 22constituting the interconnect pattern 21, and at least one plating lead44. Portions indicated by the same reference numerals as in FIG. 1 areas described above, and further description is omitted here. Theconstruction of a typical tape carrier can be applied to the mountingsubstrate 40.

The plating lead 44 is formed in a position outside the punching-outposition, that is, the outline position of the substrate 20 of thecompleted semiconductor device. Therefore, when the mounting substrate40 is punched out, the plating lead 44 can be removed. The interconnects22 are electrically connected to the plating lead 44. As a result, usingthe plating lead 44, electroplating can be carried out on theinterconnects 22.

Next, FIG. 4 shows a method of manufacturing this embodiment of themounting substrate. First, the substrate 42 which constitutes thestructure of the mounting substrate 40 from which the first and secondplating layers 30 and 32 have been removed is obtained. In this state,on the substrate 42, at least one or a plurality of the interconnectpatterns 21 and the plating lead 44 have been formed.

A plating vat 48 is filled with a plating fluid, to provide a platingbath 46. In the plating bath 46 are disposed first and second anodes 50and 52, and the above described substrate 42 is passed therebetween. Inmore detail, one surface of the substrate 42 faces the first anode 50,and the other surface faces the second anode 52. It should be noted thatif the substrate 42 is a tape, a reel-to-reel process can be applied.

When the plating lead 44 formed on the substrate 42 is connected to acathode 54 to which a potential lower than that of the anodes 50 and 52is applied, for example, a ground potential, then currents flow betweenthe plating lead 44 and interconnect pattern 21 (interconnects 22)connected thereto, and each of the first and second anodes 50 and 52. Inthis way, electroplating is applied to the surface of the interconnectpattern 21 (interconnects 22) opposite to the substrate 42, and to theportions exposed by the through holes 28, and thus the first and secondplating layers 30 and 32 can be formed.

By for example applying different voltages V1 and V2 to each of thefirst and second anodes 50 and 52, the current density of the currentflowing from each thereof is arranged to be different. By means of this,the thicknesses of the first and second plating layers 30 and 32 can bemade different.

In this way, the first and second plating layers 30 and 32 are formed onthe interconnect pattern 21 (interconnects 22), and the mountingsubstrate 40 is obtained. It should be noted that if the substrate 42 isa tape, the mounting substrate 40 is a tape carrier.

Although not shown in the drawings, portions other than those formingelectrical contacts may be covered by a permanent resist such as asolder resist, and this applies similarly to the following embodiments.In this case, plating is not applied to the portions other than thoseforming electrical contacts.

Next, the method of manufacturing a semiconductor device using thisembodiment of the mounting substrate is described. On each of theinterconnect patterns 21 formed on the above described mountingsubstrate 40 a semiconductor chip 10 is mounted by face-down bonding.For example, as shown in FIG. 1, the anisotropic conductive material 34can be used. The anisotropic conductive material 34 may be providedbeforehand on the surface of the semiconductor chip 10 on which theelectrodes 12 are formed, or may be provided beforehand on the surfaceof the mounting substrate 40 on which the interconnects 22 are formed.The anisotropic conductive material 34 may be provided to cover eachindividual interconnect pattern 21 separately, or the anisotropicconductive material 34 may be provided to cover a plurality ofinterconnect patterns 21.

As shown in FIG. 1, the conductive material 36 forming the externalterminals is provided. In this way, the plurality of semiconductor chips10 is mounted on the mounting substrate 40, and a semiconductor deviceassembly consisting of the result of integrating the plurality ofsemiconductor devices 1 is obtained.

Next, as shown in FIG. 5, the mounting substrate 40 is punched out onthe outside of each semiconductor chip 10. The form in which thepunching is carried out is not particularly restricted, but may be ashape similar to the plan view form of the semiconductor chip 10. Forthe punching out, cutting jigs 56 and 58 can be used. In this way, thesemiconductor device 1 can be fabricated continuously.

Second Embodiment

FIG. 6 shows a method of manufacturing a second embodiment of themounting substrate of the present invention. In this embodiment, thesubstrate 42 which constitutes the structure of the mounting substrate40 shown in FIG. 3, from which the first and second plating layers 30and 32 have been removed is obtained. In this state, on the substrate42, at least one or a plurality of the interconnect patterns 21 and theplating lead 44 have been formed.

First and second plating vats 60 and 62 are filled with a plating fluid,to provide sequentially first and second plating baths 64 and 66. In thefirst and second plating baths 64 and 66 are disposed first and secondanodes 68 and 70. The substrate 42 is passed through the first platingbath 64 with one surface facing the first anode 68, and next is passedthrough the second plating bath 66 with the other surface facing thesecond anode 70. It should be noted that if the substrate 42 is a tape,a reel-to-reel process can be applied.

When the plating lead 44 formed on the substrate 42 is connected to acathode 72 to which a potential lower than that of the anodes 68 and 70is applied, for example, a ground potential, then currents flow betweenthe plating lead 44 and interconnect pattern 21 (interconnects 22)connected thereto, and each of the first and second anodes 68 and 70. Inthis way, electroplating is applied to the surface of the interconnectpattern 21 (interconnects 22) opposite to the substrate 42, and to theportions exposed by the through holes 28, and thus the first and secondplating layers 30 and 32 can be formed.

By for example applying different voltages V3 and V4 to each of thefirst and second anodes 68 and 70, the current density of the currentflowing from each thereof is arranged to be different. By means of this,the thicknesses of the first and second plating layers 30 and 32 can bemade different.

In this way, the first and second plating layers 30 and 32 are formed onthe interconnect pattern 21 (interconnects 22), and the mountingsubstrate 40 shown in FIG. 3 is obtained. It should be noted that if thesubstrate 42 is a tape, the mounting substrate 40 is a tape carrier.

It should be noted that in this embodiment, the substrate 42 isconsecutively immersed in the first and second plating baths 64 and 66,but this may equally be carried out in separate immersion processes. Thefirst and second plating baths 64 and 66 are not restricted tocontaining the same metal ions, and may contain different metal ions. Inthat case, the material of the first and second plating layers 30 and 32will be different. Furthermore, both the material and the thickness ofthe first and second plating layers 30 and 32 may be made different.

Third Embodiment

FIGS. 7A and 7B show a method of manufacturing a third embodiment of themounting substrate of the present invention. In this embodiment, thesubstrate 20 is obtained with the interconnect pattern 21 (interconnects22) shown in FIG. 1 formed, but before the plating layers 30 and 32 havebeen formed.

First, as shown in FIG. 7A, the through holes 28 are filled with aresist 80. The resist 80 may be a resin, or it may be a removable tapeor the like. By means of this, the part of the interconnects 22 exposedthrough the through holes 28 is covered. Then by applying electrolessplating the exposed surface of the interconnects 22 is plated. The firstplating layer 30 on the surface of the interconnects 22 opposite to thatof the substrate 20 is formed. The first plating layer 30 has theproperties as described in the first embodiment.

Next, the resist 80 is removed, and as shown in FIG. 7B, the portions ofthe interconnects 22 not covered by the resist 80 are covered by aresist 82. The resist 82 may be a resin, or may be a removable tape.Above the surface of the interconnects 22 opposite to the substrate 20is covered by the resist 82, and within the through holes 28, a part ofthe interconnects 22 is exposed. The first plating layer 30 is coveredby the resist 82. Then when the electroless plating is carried out, theexposed surface of the interconnects 22 is plated. On the portion of theinterconnects 22 exposed within the through holes 28, the second platinglayer 32 is formed. The second plating layer 32 has the properties asdescribed in the first embodiment.

By means of the above process, as shown in FIG. 1, the substrate 20having the first and second plating layers 30 and 32 formed on theinterconnects 22 is obtained, and this forms the mounting substrate. Inthis embodiment, the order of forming the first and second platinglayers 30 and 32 is not significant. In the electroless plating step,the same material may be used for the solution and first and secondplating layers 30 and 32 formed with different thicknesses, or differentmaterials may be used for the solution and first and second platinglayers 30 and 32 formed of different materials. Further, both thematerial and thickness of the first and second plating layers 30 and 32may be made different.

When at least the thicknesses of the first and second plating layers 30and 32 are being varied, a double-sided plating layer may first beformed without applying a resist, then the resist applied to the layeropposite to the layer to be made thicker, and then further platingapplied only to the layer to be made thicker, after which the resist isremoved.

Fourth Embodiment

FIG. 8 shows a fourth embodiment of the semiconductor device of thepresent invention. A semiconductor device 2 comprises a semiconductorchip 10 and a substrate 120. The semiconductor chip 10 is that describedin the first embodiment, and has electrodes 12 and bumps 14. In thesubstrate 120 is formed a plurality of through holes 128, and in form,thickness, and substance these are the same as the substrate 20.

FIG. 9A is one plan view of the substrate of the semiconductor deviceshown in FIG. 8, and FIG. 9B is the other plan view. On one surface ofthe substrate 120 is formed a plurality of interconnects (leads) 122,constituting a first interconnect pattern 121. On each of theinterconnects 122 are formed lands 124 and 126. The first interconnectpattern 121 may be the same as the interconnect pattern 21 described inthe first embodiment. The land 126 shown in FIG. 9A has only to provideelectrical conduction between the two sides of the substrate 120, andsince no external terminals are provided, may be formed smaller than theland 26 in FIG. 1.

On the other surface of the substrate 120 is formed a plurality ofinterconnects (leads) 142, constituting a second interconnect pattern141. On each of the interconnects 142 are formed lands 144 and 146. Thesecond interconnect pattern 141 may be the same as the interconnectpattern 21 described in the first embodiment. In FIG. 9B the land 144 isformed larger, to provide for external terminals. The other land 146 hasonly to provide electrical conduction between the two sides of thesubstrate 120, and since no external terminals are provided, may beformed smaller than the land 144.

Over the plurality of through holes 128 formed on the substrate 120 passa number of the interconnects 122 and 142 formed on each of thesurfaces. The ends of the interconnects 122 and 142 may be positionedover the through holes 128. When the lands 126 and 146 are formed at theends of the interconnects 122 and 142, the lands 126 and 146 arepositioned over the through holes 128. The through holes 128 areprovided with a conductive material 148, and the interconnects 122 onone surface of the substrate 120 and the interconnects 142 on the othersurface are electrically connected.

It should be noted that holes communicating with the through holes 128may be formed in a part of the interconnects 122 and 148 on both sidesof the substrate 120, for example in the lands 126 and 146, and byplating or the like applied to the inner walls of these holes and thethrough holes 128 to provide a conductive material, the interconnects122 and 148 on both sides of the substrate 120 may be made electricallyconductive.

As shown in enlargement in FIG. 8, on the interconnects 122 formed onone surface of the substrate 120 is formed a first plating layer 130,and on the interconnects 142 formed on the other surface of thesubstrate 120 is formed a second plating layer 132. The first and secondplating layers 130 and 132 have different properties, by virtue ofdiffering in at least either of thickness or material. The first platinglayer 130 has the same properties as the first plating layer 30described in the first embodiment, and the second plating layer 132 hasthe same properties as the second plating layer 32 described in thefirst embodiment. That is to say, the first plating layer 130 has goodadhesion properties with resin, and the second plating layer 132 hasappropriate adhesion properties with the conductive material.

The semiconductor chip 10 is mounted on the substrate 120 by face-downbonding. The bumps 14 of the semiconductor chip 10 and the interconnects122 formed on one surface of the substrate 120 are electricallyconnected. Since the first plating layer 130 is formed on theinterconnects 122, a satisfactory electrical connection is obtained.When the lands 124 and 126 are formed on the interconnects 122, the oneset of lands 124 and the bumps 14 are electrically connected. As themeans of electrical connection may be used the anisotropic conductivematerial 34 comprising conductive particles included in an adhesiveformed of a resin. In this case, the conductive particles are interposedbetween the interconnects 122 and the bumps 14 and provide theelectrical connection. The anisotropic conductive material 34 may be ananisotropic conductive film or an anisotropic conductive adhesive.

When the anisotropic conductive material 34 is used, portions of theinterconnects 122 which are not in contact with the substrate 120 arecovered by the anisotropic conductive material 34. When the anisotropicconductive material 34 is not used, the portions of the interconnects122 which are not in contact with the substrate 120 are covered by aresin such as an underfill material. The material covering theinterconnects 122 may cover the whole of one surface of the substrate120. The first plating layer 130 formed on the interconnects 122 hasgood adhesion properties with resin, and therefore the resin providedover the interconnects 122 does not become detached easily.

On the interconnects 142 formed on the other side of the substrate 120is provided a conductive material 136. In more detail, the conductivematerial 136 is formed on the second plating layer 132. The conductivematerial 136 constitutes external terminals. Since the second platinglayer 132 has appropriate adhesion properties with the conductivematerial, a satisfactory electrical connection between the conductivematerial 136 and the second plating layer 132 is obtained. Theconductive material 136 is commonly solder balls, but may equallycomprise conductive projections such as plating, conductive resin, orthe like.

At this time, other than the locations of formation of externalterminals on the second plating layer 132 side may be covered by resist.In this way, for example when forming external terminals of solder, thesolder does not wet and spread to other than the locations of formingthe external terminals, and at least one of the height and positionalaccuracy of the external terminals can be maintained by the solder.

In FIG. 8, on both sides of the substrate 120, the first and secondinterconnect patterns 121 and 141 are formed, and by forming the firstand second plating layers 130 and 132, the mounting substrate isobtained. As a method of manufacturing this mounting substrate themethod shown in FIG. 4 can be applied. That is to say, one surface ofthe substrate 120 faces the first anode 50, and the other surface of thesubstrate 120 faces the second anode 52, and the method described in thefirst embodiment is applied, whereby the first and second plating layers130 and 132 of different properties can be formed.

Alternatively, as a method of manufacturing this mounting substrate, themethod shown in FIG. 6 can be applied. That is to say, one surface ofthe substrate 120 faces the first anode 68, and the other surface of thesubstrate 120 faces the second anode 70, and the method described in thesecond embodiment is applied, whereby the first and second platinglayers 130 and 132 of different properties can be formed.

Alternatively, as a method of manufacturing this mounting substrate, themethod shown in FIGS. 7A and 7B can be applied. That is to say, thefirst interconnect pattern 121 formed on one surface of the substrate120 may be covered by a first resist and electroless plating carriedout, then this resist removed, and the second interconnect pattern 141formed on the other surface of the substrate 120 covered by a secondresist and electroless plating carried out. In this case, the methoddescribed in the third embodiment is applied.

Fifth Embodiment

FIG. 10 shows a fifth embodiment of the semiconductor device of thepresent invention. A semiconductor device 3 comprises a semiconductorchip 10 and a substrate 220. The semiconductor chip 10 is that describedin the first embodiment, and has electrodes 12 and bumps 14. In thesubstrate 220 is formed a plurality of through holes 228, and in form,thickness, and substance these are the same as the substrate 20. On thesubstrate 220 is formed a plurality of interconnects 22 constituting aninterconnect pattern 221. The interconnect pattern 221 and interconnects222 may have the same construction as the interconnect pattern 21 andinterconnects 22 described in the first embodiment. The interconnects222 pass over the through holes 228.

In this embodiment, as shown in enlargement in FIG. 10, first and secondplating layers 230 and 232 are formed on the side of the interconnectpattern 222 opposite to the substrate 220. For other parts of theconstruction the same construction as is shown in the first embodimentcan be applied, and parts of the same construction are also indicated bythe same reference numerals in FIG. 10. Although not shown in FIG. 10,on exposed portions within the through holes 228 in the interconnects222, to provide the conductive material 36 to form the externalterminals, a plating layer having the same properties as the firstplating layer 32 shown in FIG. 1 may be formed.

The first plating layer 230 has good adhesion properties with resin, andmay have the same construction as the first plating layer 30 describedin the first embodiment. The second plating layer 232 has appropriateadhesion properties with the conductive material, and may have the sameconstruction as the second plating layer 32 described in the firstembodiment.

The first plating layer 230 is formed in the portion (first portion) ofthe interconnect pattern 221 (interconnects 222) contacted by the resin,and is such as to render the resin provided thereon less liable tobecoming detached. The adhesive of the anisotropic conductive material34 is an example of the resin. The second plating layer 232 is formed inthe portion (second portion) of the interconnect pattern 221(interconnects 222) bonded to the bumps 14 as the conductive material,and provides a reliable electrical connection with the semiconductorchip 10.

On the substrate 220 shown in FIG. 10, the interconnect pattern 221 isformed, and the first and second plating layers 230 and 232 are formed,to obtain the mounting substrate.

FIGS. 11A and 11B show a method of manufacturing the fifth embodiment ofthe mounting substrate of the present invention. In this embodiment, thesubstrate 220 is provided when the interconnect pattern 221(interconnects 222) shown in FIG. 10 has been formed, and before thefirst and second plating layers 230 and 232 have been formed.

First, as shown in FIG. 11A, the portion (first portion) of theinterconnect pattern 221 (interconnects 222) contacted by the resin isexposed, and on the interconnect pattern 221 (interconnects 222) aresist 240 is formed. The resist 240 is formed to exclude the portion(second portion) bonding with the conductive material. It should benoted that within the through holes 228 may also be filled with theresist 240. The resist 240 may be a resin, or may be a removable tape.Then when electroless plating is carried out, the exposed surface of theinterconnects 222 is plated. For example, the first plating layer 230 isformed on the surface of the interconnects 222 opposite to the substrate20, in the portion (first portion) contacted by the resin.

Next, the resist 240 is removed, and as shown in FIG. 11B, the portion(first portion) of the interconnects 222 contacted by the resin iscovered with a resist 242. The resist 242 may be a resin, or may be aremovable tape. Within the through holes 228, a part of theinterconnects 222 may be exposed. The first plating layer 230 is coveredby the resist 242. When electroless plating is carried out, the exposedsurface of the interconnects 222 is plated. On the portion (secondportion) of the interconnects 222 bonding with the bumps 14 the secondplating layer 232 is formed. The same plating layer may be formed on theexposed portion of the interconnects 222 within the through holes 228.

Plating can be carried out on the whole surface of the interconnectpattern 221, and after the portions other than those required, forexample other than the second portion and within the through holes 228have been covered with a resist, if further plating is carried out,plating of the necessary thickness and type can be applied to thenecessary portions only.

By means of the above process, the first and second plating layers 230and 232 are formed on the interconnects 222, and the substrate 220 isobtained, and this constitutes the mounting substrate. In thisembodiment, the order of forming the first and second plating layers 230and 232 is not significant. In the electroless plating step of formingthe first and second plating layers 230 and 232, there is no restrictionto the use of the same material for the solution, and differentmaterials may be used for the solution. In this case the first andsecond plating layers 230 and 232 are formed of different materials.Further, both the material and thickness of the first and second platinglayers 230 and 232 may be made different.

In FIG. 12 is shown a circuit board 1000 on which is mounted thisembodiment of the semiconductor device 1. For the circuit board 1000 isgenerally used an organic substrate such as a glass epoxy substrate orthe like. On the circuit board 1000, an interconnect pattern 1100 of forexample copper is formed to constitute a desired circuit, then bymechanical connection of this interconnect pattern and the externalterminals 36 of the semiconductor device 1, electrical connection isachieved.

Then as an electronic instrument 1200 equipped with the semiconductordevice 1 to which the present invention is applied, in FIG. 13 is showna notebook personal computer 1100.

It should be noted that the above-described “semiconductor element” thatis structural component of the present invention may be replaced by“electronic element,” and an electronic element (either an activeelement or a passive element) can be mounted on a substrate to fabricatean electronic component, in the same way as a semiconductor chip. Aselectronic components manufactured by using such an electronic elementmay be cited, for example, resistors, capacitors, coils, oscillators,filters, temperature sensors, thermistors, varistors, variableresistors, and fuses.

1. A method of manufacturing a mounting substrate, comprising the stepsof: immersing a substrate in a plating bath, the substrate having aplurality of through holes and an interconnect pattern formed thereonand passing over the through holes; electrically connecting theinterconnect pattern to a cathode; disposing a first anode to face thesurface of the substrate on which the interconnect pattern is formed;disposing a second anode to face the surface of the substrate oppositeto the interconnect pattern; and passing currents of different currentdensities between the first and second anodes and the cathode, wherein afirst plating layer is formed on the interconnect pattern by the currentfrom the first anode; and wherein a second plating layer is formed onthe interconnect pattern on the side of the substrate and within thethrough holes by the current from the second anode.
 2. A method ofmanufacturing a mounting substrate, comprising the steps of: immersing asubstrate in a first plating bath, the substrate having a plurality ofthrough holes and an interconnect pattern formed thereon and passingover the through holes; electrically connecting the interconnect patternto a cathode; forming a first plating layer on the interconnect patternby disposing a first anode to face the surface of the substrate on whichthe interconnect pattern is formed and carrying out electroplating;immersing the substrate in a second plating bath; electricallyconnecting the interconnect pattern to a cathode; and forming a secondplating layer on the interconnect pattern surface looking toward thesubstrate in the through holes by disposing a second anode to face thesurface of the substrate opposite to the interconnect pattern andcarrying out electroplating.
 3. A method of manufacturing a mountingsubstrate, comprising the steps of: forming a plurality of through holesand an interconnect pattern passing over the through holes on asubstrate; forming a first plating layer by covering the through holeswith a first resist and applying electroless plating to the interconnectpattern; and forming a second plating layer by exposing a portion of theinterconnect pattern in the through holes, covering the surface of theinterconnect pattern opposite to the substrate with a second resist, andapplying electroless plating to the interconnect pattern in the throughholes.
 4. A method of manufacturing a mounting substrate, comprising thesteps of: immersing a substrate in a plating bath, wherein the substratehas a first interconnect pattern formed on one surface and a secondinterconnect pattern electrically connected to the first interconnectpattern and formed on the other surface; electrically connecting thefirst and second interconnect patterns to a cathode; disposing a firstanode to face the first interconnect pattern; disposing a second anodeto face the second interconnect pattern; and passing currents ofdifferent current densities between the first and second anodes and thecathode, wherein a first plating layer is formed on the firstinterconnect pattern by the current from the first anode; and wherein asecond plating layer is formed on the second interconnect pattern by thecurrent from the second anode.
 5. A method of manufacturing a mountingsubstrate, comprising the steps of: immersing a substrate in a firstplating bath, wherein the substrate has a first interconnect patternformed on one surface and a second interconnect pattern electricallyconnected to the first interconnect pattern and formed on the othersurface; electrically connecting the first interconnect pattern to acathode; forming a first plating layer on the first interconnectpattern, by disposing a first anode to face the first interconnectpattern and carrying out electroplating; immersing the substrate in asecond plating bath; electrically connecting the second interconnectpattern to a cathode; and forming a second plating layer on the secondinterconnect pattern, by disposing a second anode to face the secondinterconnect pattern and carrying out electroplating.
 6. A method ofmanufacturing a mounting substrate, comprising the steps of: forming afirst interconnect pattern on one surface of a substrate; forming asecond interconnect pattern electrically connected to the firstinterconnect pattern on the other surface of the substrate; forming afirst plating layer by covering the second interconnect pattern with afirst resist and applying electroless plating to the first interconnectpattern; and forming a second plating layer by covering the firstinterconnect pattern with a second resist and applying electrolessplating to the second interconnect pattern.
 7. A method of manufacturinga mounting substrate, comprising the steps of: forming an interconnectpattern on a substrate; forming a first plating layer on a first portionof the interconnect pattern by covering a second portion of theinterconnect pattern with a resist and exposing the first portion, andapplying electroless plating to the interconnect pattern; and forming asecond plating layer in the second portion by covering the first portionwith a resist and exposing the second portion, and applying electrolessplating to the interconnect pattern.
 8. The method of manufacturing amounting substrate as defined in claim 1, wherein the first and secondplating layers have different properties.
 9. The method of manufacturinga mounting substrate as defined in of claim 2, wherein the first andsecond plating layers have different properties.
 10. The method ofmanufacturing a mounting substrate as defined in claim 3, wherein thefirst and second plating layers have different properties.
 11. Themethod of manufacturing a mounting substrate as defined in claim 4,wherein the first and second plating layers have different properties.12. The method of manufacturing a mounting substrate as defined in claim5, wherein the first and second plating layers have differentproperties.
 13. The method of manufacturing a mounting substrate asdefined in claim 6, wherein the first and second plating layers havedifferent properties.
 14. The method of manufacturing a mountingsubstrate as defined in claim 7, wherein the first and second platinglayers have different properties.
 15. The method of manufacturing amounting substrate as defined in claim 1, wherein the first platinglayer is formed to be thinner than the second plating layer.
 16. Themethod of manufacturing a mounting substrate as defined in claim 2,wherein the first plating layer is formed to be thinner than the secondplating layer.
 17. The method of manufacturing a mounting substrate asdefined in claim 3, wherein the first plating layer is formed to bethinner than the second plating layer.
 18. The method of manufacturing amounting substrate as defined in claim 4, wherein the first platinglayer is formed to be thinner than the second plating layer.
 19. Themethod of manufacturing a mounting substrate as defined in claim 5,wherein the first plating layer is formed to be thinner than the secondplating layer.
 20. The method of manufacturing a mounting substrate asdefined in claim 6, wherein the first plating layer is formed to bethinner than the second plating layer.
 21. The method of manufacturing amounting substrate as defined in claim 7, wherein the first platinglayer is formed to be thinner than the second plating layer.
 22. Themethod of manufacturing a mounting substrate as defined in claim 2,wherein the first and second plating layers are formed of differentmaterials.
 23. The method of manufacturing a mounting substrate asdefined in claim 3, wherein the first and second plating layers areformed of different materials.
 24. The method of manufacturing amounting substrate as defined in claim 5, wherein the first and secondplating layers are formed of different materials.
 25. The method ofmanufacturing a mounting substrate as defined in claim 6, wherein thefirst and second plating layers are formed of different materials. 26.The method of manufacturing a mounting substrate as defined in claim 7,wherein the first and second plating layers are formed of differentmaterials.